In order to be able to examine soft body tissue such as a female breast and possibly detect tumourous tissue therein, various imaging methods have been developed.
For example, mammography imaging uses X-rays which are projected through the breast and are detected after transmission such that, from the detected X-ray intensity distribution, information may be derived with respect to geometry and X-ray absorption of structures within the breast. The images acquired by a mammography X-ray projection are typically two-dimensional (2D).
As an alternative imaging technique, optical tomography has been developed. Optical tomography is a type of computer tomography that generates a digital volumetric model of an object by reconstructing three-dimensional images made from light transmitted and scattered through the object. Therein, optical tomography uses the fact that the object is typically at least partially light-transmitting or translucent. Accordingly, these techniques are best suitable for soft tissues such as present in a female breast. For example, in diffuse optical tomography (DOT) light in the near infrared spectrum is transmitted through a soft tissue object and detected after transmission. From data of detected light intensity, information about structural properties and material properties within the soft tissue volume may be derived due to differing diffusive characteristics of various tissue types. For example, information about local concentrations of oxygenated haemoglobin and deoxygenated haemoglobin may be obtained by DOT and such information may allow deriving additional information about functional properties of tissue comprised in a region of interest. Three-dimensional (3D) images may be reconstructed from such acquired optical tomography image data. The spatial resolution of e. g. diffusive optical tomography techniques is typically rather coarse, e.g. in a range of several millimeters.
Qianqian Fang; Carp, S. A.; Selb, J.; Boverman, G.; Quan Zhang; Kopans, D. B.; Moore, R. H.; Miller, E. L.; Brooks, D. H.; Boas, D. A.; , “Combined Optical Imaging and Mammography of the Healthy Breast: Optical Contrast Derived From Breast Structure and Compression,” Medical Imaging, IEEE Transactions on , vol. 28, no. 1, pp. 30-42, January 2009 doi: 10.1109/TMI.2008.925082 discloses combined X-ray mammography/diffusive optical breast imaging. However, the proposed approach still suffers from shortcomings concerning e.g. image quality and/or patient comfort.